(Original post by shengoc)
when you add water, and you still use the same volume to do the same reaction, do you think the amount of your reactant(the mole quantity) is still the same?

Nope.

as concentration change when you add water(simple dilution)

i

ahh okay, so the rate of reaction decreases because you have the same volume but due to addition of water, the concentration of the reactant deceases and thus the rate decreases and goes to curve shape.

(Original post by topboim)
ahh okay, so the rate of reaction decreases because you have the same volume but due to addition of water, the concentration of the reactant deceases and thus the rate decreases and goes to curve shape.

it is really the amount that reacts that matters, so if you use the same volume of reactant A(say conc = 1 M ) and reactant B(say conc = 0.1 M )

where A and B are the same solutions with different concentrations.

In 1 dm cube, mol of A = 1 mol and mol of B = 0.1 mol

If what A and B reacts with is to be present in excess, and also if A(or B) is present in the rate equation, then you can see that amount of A or B does affect the rate.